FIG. 1 depicts an air-bearing surface (ABS) view of a conventional magnetic recording transducer 10 during formation. The magnetic recording transducer 10 may be a perpendicular magnetic recording (PMR) head or a heat assisted magnetic recording (HAMR) head. The conventional transducer 10 includes an underlayer 12 on which a photoresist mask 14 has been formed. During formation of the photoresist mask 14, a bottom antireflective coating 16 has been used. The photoresist mask 15 has an aperture in which the pole 20 is formed. The pole 20 has pole sidewalls 22 and 24 having a shape that matches the sidewalls of the aperture in the photoresist mask 14. As can be seen in FIG. 1, the main pole 20, and photoresist mask 14, have a width d1 at the bottom of the trench and a height d2. The aspect ratio of the main pole 20, the height of the main pole/aperture and divided by the width at the bottom (d2/d1) is desired to be large.
Although the conventional magnetic recording head 10 functions, there are drawbacks. In particular, the sidewalls 22 and 24 of the main pole 20 may not be vertical. Particularly for a main pole 20 having a high aspect ratio of greater than five, the top of the aperture, and thus the main pole 20, may be noticeably wider than the bottom. In addition, the sidewall angle changes near the top of the pole, as depicted in FIG. 1. This issue is exacerbated at lower pole widths, such as on the order of two hundred nanometer or less. Such low width poles may be formed by trimming the main pole 20. However, it in some cases, such an operation is undesirable. Accordingly, what is needed is a system and method for improving the performance of a magnetic recording head.